The invention relates to a vehicle lighting device with an optical conductor system in accordance with the generically determinative features of Claim 1.
A vehicle lighting unit with an optical conductor system is disclosed in DE 196 13 211 A1. This device has a light source whose light is focused into an optical rod. At specific points, light is coupled out of the rod by means of reflecting facets and guided by optical lenses onto the desired lighting field. The longitudinal axis of the optical conductor forms an acute angle relative to the facets, the inclination of the facets being dimensioned such that total reflection occurs at the facets.
In the case of this type of lighting system, it is disadvantageous that the arrangement of the facets with the assigned optical lenses permanently prescribes the resulting light distribution. This prescription determines the characteristic of the headlamp. The possibilities for changes to the light distribution are greatly limited.
In order to influence the light distribution, it is conceivable for there to be present in the light transmission controllable elements which are fitted, for example, between the light source and rod or upstream of the respective lens. In addition to mechanical shutters, it seems particularly attractive to use electrochromic elements which can be switched between transparent and absorbing by applying an electric voltage, and thus serve to control the light distribution of the individual facets. However, such elements can be used only in a limited way, since they heat up very strongly in the darkened state and it is not possible to use the dipped light fraction. Controlling the light distribution via a reflection principle is therefore to be preferred in every case.
The object of the invention is to improve a light system so as to permit the light distribution to be changed simply and quickly in the case of vehicle headlamps, in particular the light distribution on the road.
According to the invention, the object is achieved by the features of Claim 1. Advantageous refinements and developments of the subject-matter of the invention are characterized by the features of the subclaims.
A substantial advantage of these refinements consists in that a multiplicity of light distributions on the road are rendered possible by changing individual light-controlling elements. Thus, even quick changes of light distribution on the road are possible when, for example, the aim is to switch over from dipped beam to main beam, or when the aim is to implement a different light distribution such as, for example, a cornering light.